This invention relates generally to semi-automatic firearms and relates more particularly to the means by which recoil components are retained within the firearm.
The type of firearm with which this invention is concerned includes a receiver, a slide mounted upon the receiver for reciprocating movement relative thereto between forward and rearward limits of travel, and a barrel positioned within the slide. A barrel bushing is interposed between the slide and the barrel for movement with the slide during reciprocating movement thereof. A recoil spring is connected between the receiver and the slide for urging the slide to its forward limit of travel, and a recoil spring plug is interposed between the spring and the slide for holding one end of the spring within the slide and so that forces, such as those generated by the firing of a cartridge within the firearm and utilized to move the slide toward its rearward limit of travel are transferred from the slide to the recoil spring through and contained by the recoil spring plug. Moreover, the recoil spring plug is movable relative to the slide between a rearward position at which disassembly of the firearm is facilitated and a forward position at which the firearm is ready for firing. An example of a firearm of the aforedescribed type is available under the trade designation Colt MK IV/Series 80 Government Model from Colt's P.T. F.A. Mfg. Co., Hartford, Conn..
When a firearm of the aforedescribed type is discharged, the explosive gases generated within the barrel suddenly urge the slide from its forward limit of travel toward its rearward limit of travel so that a relatively large amount of force is suddenly transferred from the slide to the recoil spring and to the recoil spring plug. In the referenced Colt firearm as manufactured heretofore, the recoil spring plug includes a projecting lug which is received within a slot defined within the slide so that a substantial amount of slide-moving forces which are transferred from the slide to the recoil spring plug are passed to the projecting lug. It has been found that the projecting lug is susceptible to shearing off during the transfer of such slide-moving forces so that the recoil spring plug loses its spring-holding capacity and at times literally is projected out of the slide with considerable force and possibly endangering the user or others.
The recoil spring plug is a hollow cylinder having one open end and one closed end for containing one end of the recoil spring. To avoid excessive protrusion of one end of the recoil spring plug beyond the barrel and the barrel bushing at the muzzle end of the firearm and to prevent the end of recoil spring plug opposite its protruding end from hitting the receiver, the overall length of the spring recoil plug is limited to a length just slightly longer than that of the recoil spring when fully compressed. This full compression of the recoil spring occurs when the slide is in its rearward limit of travel. To accommodate the full spring compression, the wall thickness of the closed end of the recoil spring plug is minimized.
Further, the wall thickness of the barrel bushing and the recoil spring plug are on the order of a couple of a tenths of an inch due to the necessity of conserving sufficient space to permit the barrel to be flared or cone-shaped at the muzzle end. This minimized wall thickness is largely responsible for the failure of the recoil spring plug and the barrel bushing when subjected to the recoil forces encountered in the larger calibers that are found in this type of pistol. This overall design places severe limitations upon the possible engineering techniques available for securing the barrel bushing and recoil spring plug in their respective positions while still providing for the desired "tool-less" field stripping as has become traditional for this type of firearm.
It is recognized that cylindrical pins, for example, have been used heretofore to anchor the recoil spring plug in the slide. Such pins and screws, however, tend to work their way out of their locking positions during firing of the weapon. In the present firearm, in any event, such pins are not usable due to the lack of sufficient space. Specifically, because the recoil spring is received within the recoil spring plug, it is not possible to insert a pin through the plug inasmuch as such pin would obstruct the recoil spring and its action. A cylindrical pin that possesses sufficient strength to not be sheared upon recoil of the slide is too large to be positioned between the barrel bushing and the recoil spring plug while permitting clearance for the barrel within the barrel bushing and for the recoil spring within the recoil spring plug, due to the thin walls of the barrel bushing and recoil spring plug. Additionally, a screw mounted through the forward (i.e., muzzle) end of the recoil spring plug tends to unthread itself due to recoil impact and torque.
It is an object of the present invention to provide a new improved system for locking the recoil components of a firearm of the aforedescribed type into place.
Another object of the present invention is to provide such a system utilizing components wherein the likelihood of failure, such as shear failure, of the components during use of the firearm is relatively small.
Still another object of the present invention is to provide such a system wherein the likelihood of a system component accidentally dislodging itself from its operative position within the firearm is relatively small.
Yet another object of the present invention is to provide such a system utilizing components which are relatively easy to assemble and disassemble.
A further object of the present invention is to provide such a system having components which can be manufactured economically.
A still further object of the present invention is to provide such a system which is uncomplicated in construction and effective in use.
In one aspect of the present invention, the slide defines a transversely-extending through-aperture and each of the recoil spring plug and barrel bushing defines a transversely-extending slot which is positioned in registry with the slide through-aperture so as to provide a transversely-extending through-opening in the firearm when the recoil spring plug is positioned in either one of its limited rearward and forward positions. The firearm also includes an elongated lockplate member insertable endwise within the defined through-opening when the recoil spring plug is depressed to its rearward position for securing the recoil spring plug within the slide and which cooperates with the recoil spring plug so that the lockplate member is prevented from being moved endwise along and out of the through-opening when the recoil spring plug is released to its limited forward position.
In another aspect of the invention, the transversely-extending through-opening in the firearm is collectively provided by a though-aperture defined in the slide and slots defined in the recoil spring plug and the barrel bushing. When inserted within the through-opening, the lockplate member is in position to transfer energy utilized to shift the slide toward its rearward limit of travel to the recoil spring plug by way of the slide and barrel bushing.